Hydrotreating processes are used by petroleum refiners to remove heteroatoms, including sulfur and nitrogen from hydrocarbonaceous streams such as naphtha, kerosene, diesel, gas oil, vacuum gas oil (VGO), and vacuum residue. Hydrotreating severity is selected to balance desired product yield against the desired lower levels of heteroatoms. Increasing regulatory pressure in the United States and abroad has resulted in a trend to increasing the severity and/or selectivity of hydrotreating processes to from hydrocarbon products having very low levels of sulfur.
Hydrotreating is generally accomplished by contacting a hydrocarbonaceous feedstock in a hydrotreating reaction vessel or zone with a suitable hydrotreating catalyst under conditions of elevated temperature and pressure in the presence of a hydrogen-containing treat gas to yield a product having the desired lower level of sulfur. The operating conditions and the hydrotreating catalysts utilized will influence the quality of the hydrotreated products.
Although various hydrotreating processes are practiced commercially, there is still a need in the art for improved hydrotreating processes that can be practiced more efficiently with higher hydrotreating severity or capacity.